Buyers hoping to purchase the upcoming fourth-generation Toyota Prius are going to have to wait until December 2015, as Automotive News reports production has been delayed from the originally planned spring 2015 launch. The exact reasons for the delay are unclear, but the most likely one is that project engineers need to work out details and make adjustments on the new range-wide modular platform, as well as an updated next-generation hybrid drivetrain system.

The next-gen Prius, codenamed 690A, will ride on Toyota’s new modular vehicle platform. Dubbed the Toyota New Global Architecture, this modular approach to chassis and components keeps the overall production cost down, while increasing quality across the board. This aids in ensuring the consumer pays less for repairs and maintenance.

Along with an updated chassis and platform, the fourth-gen Prius will debut the next generation of hybrid technology. Development goals include increasing efficiency by 10 percent over the previous hybrid drivetrain. “We need to prioritize fuel-efficiency,” said Satoshi Ogiso, managing officer for Toyota product planning, to AN. This next generation of hybrid technology will be developed to give engineers access to a wide range of engines and platforms, moving beyond availability for just the Camry-based vehicles.

One piece of technology that's too far out to make it in time for the fourth-gen Prius is an energy-saving computer chip revealed by Toyota back in May. The chip is composed of silicon carbide as opposed to traditional silicon. The new silicon carbide chips undergo only a tenth of the energy loss experienced by conventional silicon chips. Expect to see this new innovation implemented by 2020.

What's interesting about this 4th gen Prius article is not the car itself or its HSD technology (someone has to invent a cheaper and more energy-retaining material for batteries than lithium before full customer acceptance) it's the fact Toyota is folding at least the Avensis/JDM Camry and NoAm Camry platform families into one (ranging from the Scion tC coupé all the way to the Avalon/Lexus ES sedán and the Highlander/next gen Lexus RX crossover), like VW/Auto Union is doing with their MQB (transversal engined FWD's) and MLB (longitudinal engined FWD's) platform families.

Toyota wouldn't be ashamed to tell the 4th gen Prius is Camry-based (SWB replacing JDM's, LWB replacing NoAm's) as they are today of the 3rd gen on the Avensis/JDM Camry platform family...

With this modular lineup I can see at least another similar platform family for all their FWD vehicles of Corolla XII (next one) size and below (even bringing to NoAm the Aygo [Fiat 500/Spark/Mirage-sized] successor, brought from a cheap-labor country). RWD (BMW's? Supra successor, Lexus IS/RC,GS and LS...) vehicles would continue to be separated.

You can spin this as a positive, or a negative, but "The Spin" doesn't really matter. This is Toyota's market to set, and they'll bring the new Prius when it's ready, and not before. They'll sell 225-240k Prius this year, and nobody else is going to stop them. It takes a little more to make a 55 MPG Prius.

Toyota uses the analogy of asking Usain Bolt to run 100M 10% faster (in 8.8 seconds) vs Toyota giving a car already at 50 MPG another 5 MPG more efficiency. Plus Toyota wants to make the car more powerful, lighter, faster, more fun to drive, more aggressive styling, and add an AWD model.

@Black Dynamite Online Yes. Other online reports say much the same thing. Toyota wants to make sure they make it not just good, but as best as can be. They've indicated lithium-ions will finally come into play as well, though perhaps slowly. Like you said, Toyota will continue to sell this vehicle in large numbers, and the 10% increase in fuel efficiency will make it even more appealing than today's Prius. I'm sure it will continue to be the number one selling vehicle in California as well. It is also likely to be more desirable as some states, like here in Nevada, are discussing the option of fuel taxing EVs at registration as they do not pay federal fuel tax at gas pumps...yet still use the highways. Because of its stingy use of fuel, Prius owners may end up paying the least in fuel tax and no EV registration tax!